Today, many printers, both commercial and non-commercial, are capable of printing many types of print jobs. A print job includes both the documents that are to be printed and the printing instructions associated with those documents. The printing instructions (the “job selection”) may specify almost any attribute the printed document is to have including but not limited to, the number of copies, and the type of ink (toner), paper, and font to be used, and may be specified by a customer, or other individual or mandated by the type of print job. Because different types of toner may be required or desired for different print jobs, some printers are capable of printing with a variety of toner types. These “multi-toner” printers enable printing for almost every conceivable purpose, application and industry and are limited only by the types of toner available. The almost limitless range of colors available enable printing for virtually any type of commercial, personal, or artistic endeavor. Additionally, toner is available in magnetically-readable form which allows magnetically-readable characters to be printed. Types of toner include, but are not limited to, toners of various colors, and toner in magnetically-readable and non-magnetically readable form, which may also come in various colors.
In order to accommodate the use of many different types of toner, various methods and mechanisms have been devised. For instance, many multi-toner printers available for personal use, such as personal laser printers, are adapted to use exchangeable toner cartridges that may each contain a different type of toner. In another example, some commercial multi-toner printers are adapted to use exchangeable toner stations, wherein each toner station contains a different type of toner. In some cases, each toner station may be dedicated to a single toner or type of toner. Hereinafter, the term “toner holder” will be used to designate any exchangeable container for holding toner, including toner stations and toner cartridges.
One desirable feature for multi-toner printers to have is the ability to determine the type of toner currently installed in the printer. This feature is particularly desirable for commercial printers that print with both magnetically-readable and non-magnetically-readable toner. Magnetically-readable toner is used to create documents that will be read using some type of magnetic ink character recognition (“MICR”) method, often without the aid of human intervention. These MICR documents may be, for example, financial documents such as checks. Because these MICR documents will be read magnetically, it is crucial that magnetically-readable toner (“MICR toner”) be used when the MICR documents are printed. Additionally, because MICR toner is significantly more expensive than non-magnetically-readable (“standard toner”), it is also important that documents that do not have to be magnetically read (“standard documents”) are not printed with MICR toner.
One method for determining the type of toner installed in a multi-toner printer is, of course, visual inspection of the toner holder by a person. However, people often forget to make such an inspection, particularly in rushed or otherwise stressed situations. In the case of a large print job, many pages may be printed and wasted before the incorrect toner is identified, if ever. Another known method for use with multi-toner printers that use exchangeable toner stations includes visual inspection by a laser scanner. U.S. Pat. No. 6,236,816 discloses a method that uses unique barcodes placed on toner stations wherein each of the barcode identifies the type of toner inside the toner station on which it is located. When a toner station is coupled to a printer, a laser scanner located in the printer optically reads the barcode to obtain a barcode reading. A processor then matches the barcode reading with entries in a table in order to identify the coupled toner station. Unfortunately, this method requires the use of an expensive laser scanner.